Flight system

ABSTRACT

A disclosed device allows a person to fly. A disclosed wearable flight system includes a plurality of propulsion assemblies including a left-hand propulsion assembly configured to be worn on a user&#39;s left hand and/or forearm and a right-hand propulsion assembly configured to be worn on a user&#39;s right hand and/or forearm. A further embodiment includes a body propulsion device that is configured to provide a net force along an axis defining a net body propulsion vector and a support device configured to support a user&#39;s waist or torso. The support device is configured to hold a user&#39;s body relative to the body propulsion device such that a line extending between center the of the user&#39;s head and the center of the user&#39;s waist extends, relative to the orientation of the net body propulsion vector during use, by a body propulsion elevation angle that is greater than zero.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/666,052, filed Feb. 7, 2022, which is a divisional of U.S. patentapplication Ser. No. 16/488,111, filed Aug. 22, 2019, issued as U.S.Pat. No. 11,279,482, which is a national stage entry under 35 U.S.C. of371 of PCT Patent Application No. PCT/GB2018/050449, filed Feb. 21,2018, which claims priority to United Kingdom Patent Application No.1702852.3, filed Feb. 22, 2017, the entire contents of each of which areincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

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INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR ASA TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

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BACKGROUND

This disclosure relates to an apparatus that allows an individual tofly. For example, the disclosure relates to the provision of propulsionassemblies that can be held in a user's hands and/or worn on a user'sforearms and provide thrust to lift the user from the ground.

There have been many attempts in the past to allow individuals to flywith only minimal equipment. Typically, such systems are formed of aframework that rigidly connects one or more propulsion devices with eachother or with a wing.

BRIEF SUMMARY OF THE DISCLOSURE

The inventors have realized that it is possible to configure a flightsystem that can use the strength of the human body, rather than a rigidframe work, to provide stable flight for an individual.

Accordingly, there is provided a wearable flight system and a propulsionassembly as defined by the claims.

By propulsion assembly is meant a device that produces thrust. Apropulsion assembly may include one or more propulsion devices that eachprovide thrust (for example, in a known direction) and collectivelydefine the thrust that is produced by the propulsion assembly. Thethrust provided by a propulsion assembly produces an equal and oppositeforce on the user. Each propulsion assembly is able to provide a maximumthrust of at least 400N and in some embodiments at least 500N. Eachpropulsion assembly may be controllable to produce a lower thrust thanthe maximum based on control signals. The propulsion assemblies mayinclude turbines or ducted fans.

By “wearable” is meant that propulsion assemblies of the flight system(those parts that provide thrust) may be mounted on the human body suchthat the “wearer” contributes at least in part to the relative motion ofthose propulsion assemblies. That is, it is recognized that thedifficult control problem of correctly angling a variety of thrustsproduced by a plurality of propulsion assemblies may be delegated to thewearer's natural senses of balance, proprioception, and kinesthesia.

Embodiments of the disclosure include a flight system comprising atleast two propulsion assemblies that may be held in the hands and/orotherwise mounted on the wearer's forearms.

In such a system, net thrust is directed substantially in line with theuser's respective forearm and away from the elbow so that the inducedstress is generally aligned with the bones of the wearer's forearm andis directed outwardly. Here, reference is made to net thrust rather thanall thrust. There may be multiple propulsion devices that individuallyproduce thrust that is not aligned with the wearer's arm, butcollectively for each propulsion device the net thrust (the resolutionof the generated forces) will be so aligned.

A suitably physically conditioned wearer is able to support his/her ownweight using just his/her arms, but for longer usage, it may beadvantageous to share some of the load with other parts of the wearer'sskeleton or musculature. Optionally, therefore, there may additionallybe provided a body propulsion assembly arranged for engaging thewearer's torso to substantially prevent relative movement between thebody propulsion assembly and the wearer's torso. In addition, oralternatively, one or more leg propulsion assemblies (either one forboth legs or one for each leg) can be provided. The leg propulsionassemblies may be arranged for engaging one or both of the wearer's legsto substantially prevent relative movement between the leg propulsionassemblies and the wearer's corresponding leg(s).

In various embodiments, however, half or the majority of the load iscarried by the left-hand and right-hand propulsion assembliescollectively. In other words, the maximum thrust capability of theleft-hand and right-hand propulsion assemblies together may be equal toor greater than the maximum thrust capability of the other propulsionassemblies combined.

In fact, it has been found that providing a thrust roughly equal betweeneach of: the left-hand propulsion assembly; the right-hand propulsionassembly; and, collectively, the other propulsion assemblies, provideeven more stability (i.e., tripod-like balance between each arm and thebody). Therefore, the maximum thrust capability of the left-hand andright-hand propulsion assemblies together may be equal and the maximumthrust capability of each of the left-hand and right-hand propulsionassemblies may be equal to or greater than the maximum thrust capabilityof the other propulsion assemblies combined.

Lift is produced by the combined vertical resolution of the forcesgenerated by all of the propulsion assemblies. Whilst not essential, forreasons of control and stability the thrust generated by the left-handand right-hand propulsion assemblies is equal. In order to controlhorizontal motion, the wearer can use his/her arms to direct theleft-hand and right-hand propulsion assemblies to produce a net thrustthat includes a horizontal component.

When a body propulsion assembly is provided, this may be inclinedrelative to the torso of the wearer (by virtue of the arrangement of asupport through which it engages the wearer) so as to provide a smallnet forward force on the wearer, i.e. the thrust is directed rearwardlyto produce a net force on the wearer in a forward directionperpendicular to a line extending between the center of the user's headand the center of the user's waist. In other words, with the wearersupported in an upright position, the body propulsion assembly mayprovide a net forward force. That forward force may be counteracted bythe wearer inclining his/her arms in front of his/her torso to providean equal net thrust in the opposite direction. Thus, the assemblies arearranged such that collectively they can produce equilibrium (a netvertical thrust equal to the load of the wearer and flight system, witha zero net horizontal thrust) when in a splayed (i.e. divergent)arrangement. Of course, this also has the advantage that the exhaust ofthe propulsion assemblies is directed away from the wearer's body.

When a body propulsion assembly is provided, it may be arrangedvertically at the same height as the left-hand and right-hand propulsionassemblies when in the splayed arrangement that produces equilibrium. Ithas been found that a good location on the body of the wearer istherefore in the region of the wearer's waist (that is, the thrust isgenerated near the wearer's waist). The outlet of the thrust is nohigher than the user's lumbar vertebrae and no lower than the user'sthighs. The outlet of the thrust may be aligned with the user's lumbarvertebrae.

Among other advantages, in the case that turbines or fans are used toprovide thrust, this ensures that the air take in by one propulsionassembly is not fed by the outlet of another propulsion assembly.

In optional embodiments, a fuel tank supplies fuel to the propulsionassemblies (for example, the fuel may supply turbines forming thepropulsion devices). Since the user is flying based on feel, it isimportant that the experience remains constant over time so that theuser does not need to greatly re-calibrate his or her actions as thefuel is used up. Accordingly, the thrust provided by one or more or allof the propulsion assemblies can be automatically varied as a functionof the stored fuel. That is the fuel use (or the remaining stored fuel)may be monitored, and the thrust provided by the propulsion assembliesmay be used to compensate for the reduction in weight of the fuel load.Fuel use/remaining fuel may be measured directly, or inferred either bythe use of one or more propulsion devices.

Since the fuel store may be carried on the user's back, it isadvantageous in that case that the thrust of a body propulsion assembly(since this will be located most closely to the fuel store) is varied asa function of the stored fuel. The thrust of the body propulsionassembly is automatically reduced to compensate for the reducing load ofthe fuel store as fuel is used.

In various embodiments, the propulsion assemblies configured to be wornon a user's hand or forearm may include at least two hand propulsiondevices in a splayed arrangement that produce thrusts that diverge suchthat their net thrust is substantially aligned with the wearer's arm.This has been found to add to the stability of the overall system.

The flight system of the disclosure may be provided with or without oneor more wings. However, the features set out below make it unnecessaryto use a wing.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a better understanding of the disclosure, and to show how the samemay be put into effect, reference will now be made, by way of exampleonly, to the accompanying drawings in which:

FIGS. 1 a to 1 c show a first propulsion assembly for use in anembodiment of the disclosure;

FIGS. 2 a to 2 c show a second propulsion assembly for use in anembodiment of the disclosure;

FIGS. 3 a to 3 e show a first embodiment of a flight system inaccordance with the disclosure;

FIGS. 4 a to 4 c show a third propulsion assembly for use in anembodiment of the disclosure;

FIGS. 5 a to 5 d show a second embodiment of a flight system inaccordance with the disclosure; and

FIGS. 6 a to 6 d show a third embodiment of a flight system inaccordance with the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

A first embodiment of a propulsion assembly 100 for applying thrustdirectly to a user's arm is shown in FIGS. 1 a to 1 c . Of course, it isintended that a flight system in accordance with the disclosure willhave one propulsion assembly 100 for each arm.

With reference to FIG. 1 a , a propulsion assembly 100 includes: one ormore propulsion devices 110; a sleeve 120; and one or more mountings118.

In the depicted embodiment there are two propulsion devices 110, a firstpropulsion device 110 a, and a second propulsion device 110 b. Forthe/each propulsion device 110 a, 110 b, there is a mounting 118 a, 118b via which the respective propulsion device 110 a, 110 b may be mountedto the sleeve 120.

The sleeve 120 of the propulsion assembly 100 is configured to be wornon a user's hand and/or forearm. It is advantageous that the sleeve 120extends over a length of from 20 cm to 50 cm, and in some embodiments alength of from 30 cm to 35 cm, so that the propulsion assembly 100 isheld in alignment with the user's arm, but does not hinder articulationof the elbow. The sleeve 120 defines a longitudinal axis, a distal end121 and a proximal end 122. When the propulsion assembly 100 is worn,the distal end 121 is distal with respect to the user's body (e.g.nearer the user's hand) and the proximal end 122 is proximal withrespect to the user's body (e.g. nearer the user's elbow). The sleeve120 may have a diameter in the range 8 cm to 10 cm.

The sleeve 120 is padded on the inside. The padding may be shaped to thegeneral contour of an arm so as to distribute support comfortably.

Irrespective of the number of propulsion devices 110, the propulsionassembly 100 as a whole is arranged to provide a net thrust along anaxis that generally corresponds with the user's forearm when thepropulsion assembly 100 is worn. That is, the propulsion assembly 100 asa whole is arranged to provide a net thrust along the longitudinal axisof the sleeve 120.

The first and second propulsion devices 110 a, 110 b are angled apart soas to produce thrust along non-parallel vectors. For example, themountings 118 a and 118 b may include connecting members 130 that spacethe propulsion devices 110 a, 110 b from the sleeve 120 by a greateramount at the distal end 121 than at the proximal end 122.

The first propulsion device 110 a is arranged to provide net force alonga first axis Xa defining a first propulsion vector. The secondpropulsion device 110 b is arranged to provide net force along a secondaxis Xb defining a second propulsion vector.

It has been found that the divergence of thrust can provide beneficialstability. Therefore, the first propulsion vector is at least an angleof 5° relative to the second propulsion vector and in some embodimentsat least an angle of 10°. Furthermore, it is advantageous that the firstpropulsion vector is no more than an angle of 30° relative to the secondpropulsion vector and in some embodiments no more than 25°. By remainingwithin this range, the loss of thrust due to divergence can be balancedagainst the improved stability.

As best shown in FIG. 1 b , within the sleeve 120 there is provided ahandle 124 for the user to grasp. The handle 124 may have mountedthereon controls 126. The controls 126 face the distal end 121 of thesleeve 120. In this way, when a portion of the user's weight is appliedto the handle for support, the user's fingers will be free to manipulatethe controls 126. The handle 124 is ergonomically-shaped so as todistribute the user's weight over as large an area of the user's hand aspossible. As a result, a left-hand propulsion assembly 100 may have aleft-handed grip 124, while a right-hand propulsion assembly 100 mayhave a right-handed grip 124. One or both of the left-hand grip 124 andright-hand grip 124 will have controls 126 mounted thereon.

As in this embodiment, when first and second propulsion devices 110 a,110 b are provided, the handle may be positioned such that it is alignedwith a line extending between the first and second propulsion devices110 a, 110 b. This defines the position of the first and secondpropulsion devices 110 a, 110 b relative to the user's closed fist, andhas been found to be particularly stable.

The inventors have realized that the position of the handle 124 relativeto the outlet(s) of the propulsion device(s) 110 of the propulsionassembly 100 can influence stability. The handle 124 may be spacedbeyond the outlet(s) of the propulsion assembly 100 (e.g. the outlets ofthe first and second propulsion devices 110 a, 110 b) by a distance inthe range 20 mm to 100 mm, and in some embodiments by 30 mm to 60 mm, insome embodiments by 40 mm.

That is to say that the handle 124 may be spaced by this distance beyondthe outlets in a direction corresponding to the axis of the net thrustPut another way, the handle 124 may be spaced by this distance beyondthe outlets in a direction corresponding to the longitudinal axis of thesleeve 120 if provided.

The handle 124 may be spaced by this distance beyond the outlets in adirection corresponding to the axis that generally corresponds with theuser's forearm when the propulsion assembly 100 is worn.

The controls 126 include two input devices. The first of the inputdevices provides a variable signal and can be used to control an amountof thrust produced by a propulsion assembly 100 (or a set of propulsionassemblies 100). The second of the input devices provides a binaryoutput and can be used to deactivate one or more or all of thepropulsion assemblies 100 of the flight system when released. It is notessential that both left-hand and right-hand propulsion assemblies 100include the second input device. The second of the input devices may bea “kill switch”. That is, it must remain depressed by the user in orderto prevent deactivation of the propulsion assemblies 100.

The controls 126 are mounted on the handle so as to align with the thumband forefinger of the user. The first input device is therefore in theform of a trigger aligned with the user's index finger (when the handleis held in the user's hand). The second input device may be aligned withthe user's thumb (when the handle is held in the user's hand) so that itcan be continually held down during use of the flight system to preventdeactivation.

A first embodiment of a propulsion assembly 200 for a user's torso isshown in FIGS. 2 a to 2 c . In some embodiments a flight system inaccordance with the disclosure will have one such propulsion assembly200.

Body propulsion assembly 200 is configured to apply thrust directly to auser's torso and includes at least one body propulsion device 210 and asupport 220.

The support 220 is arranged to support a user's waist or torso. Forexample, it may include a seat, harness, belt, jacket, and/or other itemof clothing for securing the at least one body propulsion device 210 toa user's body. The at least one body propulsion device 210 is supportedon the dorsal side of the user's body

The support may be configured to be worn on a user's back or waist, butin either case it is advantageous that the support is sized and shapedsuch that the location at which thrust is generated by the at least onebody propulsion device(s) 210 (i.e. the nozzle of the body propulsiondevice(s) 210 when these are turbines and/or the fan of a fan driven bya motor) is located between the lower edge of the rib cage and knees,and in some embodiments between the upper extent of the lumbar vertebraeand the user's upper thigh.

The support may be sized and shaped such that the location at whichthrust is generated by the at least one body propulsion device(s) 210(i.e. the nozzle of the body propulsion device(s) 210 when these areturbines and/or the fan of a fan driven by a motor) is aligned with thelumbar vertebrae.

The support 220 is arranged to hold the at least one body propulsiondevice 210 at a fixed angle relative to the user's torso when the bodypropulsion assembly 200 is worn by (i.e. engages) the user. The support220 defines an axis Z, which is parallel with a line extending betweenthe center of the user's head and the center of the user's waist whenthe support is worn.

The support 220 holds the at least one body propulsion device 210 at anangle to the axis Z. That angle has an elevation component, the bodypropulsion elevation angle W. That is, the body propulsion elevationangle W is the angle in the sagittal plane (the plane that divides theuser into left and right sides) between the net thrust produced by thebody propulsion assembly 200 and the axis Z.

In other words, the support 220 is configured to hold a user's bodyrelative to the at least one body propulsion device 210 such that a lineextending between the center of the user's head and the center of theuser's waist extends relative to the orientation of the net thrustprovided by the body propulsion assembly 200 by the body propulsionelevation angle W.

The body propulsion elevation angle W is greater than zero. The bodypropulsion elevation angle W is at least 10° and in some embodiments atleast 12°. In some embodiments, the body propulsion elevation angle W isno more than 30° degrees and in some embodiments no more than 18°.

This choice of angle has been found to improve stability and protect theuser's legs without greatly reducing total lift.

As can be best seen in FIGS. 2 b and 2 c , one optionally way ofmaintaining the body propulsion elevation angle W relative to the user'slegs is by providing the support with leg braces 240 for engaging theuser's upper thighs. A leg brace 240 may include a section 244 arrangedto extend between the user's legs so that the legs may grip the legbrace 240. The leg brace 240 may also have a wider section 242 on whicha user may sit.

Although a single body propulsion device is sufficient, the bodypropulsion assembly 200 may include at least a first body propulsiondevice 210 a and a second body propulsion device 210 b. The first bodypropulsion device 210 a is arranged to provide net force along a firstaxis Ya defining a first propulsion vector. The second body propulsiondevice 210 b is arranged to provide net force along a second axis Ybdefining a second propulsion vector. The first propulsion vector is notparallel with the second propulsion vector. The first and secondpropulsion vectors are directed apart by an angle of at least 5° and insome embodiments at least 20°. In some embodiments, the first and secondbody propulsion vectors are directed apart by an angle of no more than30°.

A first embodiment of a flight system is shown in FIGS. 3 a to 3 e , inwhich it can be seen that the system includes a left-hand propulsionassembly 100 (of the type discussed above with reference to FIGS. 1 a to1 c ); a right-hand propulsion assembly 100 (of the type discussed abovewith reference to FIGS. 1 a to 1 c ); a body propulsion assembly 200 (ofthe type discussed above with reference to FIGS. 2 a to 2 c ).

Each propulsion assembly 100, 200 is able to provide a maximum thrust inthe range 400N to 500N.

FIGS. 3 a to 3 e show an embodiment in which two propulsion devices 110are provided for each of the left-hand and right-hand propulsionassemblies 100. Also in some embodiments is the provision of twopropulsion devices 210 for the body propulsion assembly 200. That is, acombination of six propulsion devices 110, 210, with two for each armand two for the user's torso. Also shown is the above-described rearwardorientation of the propulsion devices 210 of the body propulsionassembly 200 when the user assumes an upright standing posture.

As discussed above, the support 220 of the body propulsion assembly 200is sized and shaped to hold the body propulsion devices 210 so thatthrust is produced at a height between the lower edge of the rib cageand knees, and may be level with the lumbar vertebrae.

The flight system 300 also includes an energy storage device 310 forproviding power to the propulsion assemblies. This may include a fuelstorage vessel for supplying fuel to turbines and/or batteries forpowering fans and/or control circuitry. The energy storage device 310may be provided in the form of a back-pack to be worn above alower-back-mounted or waist-mounted body propulsion assembly 200, orwhich may have one or more propulsion devices attached thereto (forexample, one either side of a central fuel storage vessel).

Since the flight system 300 may be provided without a wing (i.e. it maybe solely dependent upon the propulsion assemblies to provide lift), itis beneficial to minimize interruptions in the thrust provided by anyone propulsion device 110, 210, 410. One source of interruptions, in thecase in which the propulsion assemblies include turbines, is thepossibility of a bubble in the fuel line. This can potentially cause amomentary loss of thrust or even shut down the engine. It isadvantageous that when the energy storage device 310 includes a fuelstorage vessel, the vessel is provided as a variable volume storage (forexample, a bladder or a cylinder closed by a piston) rather than a fixedvolume chamber. In this way, no air will be present in the fuel storagevessel. 25. Embodiments include a bubble sensor for sensing the presenceof bubbles in fuel supply lines for supplying fuel to turbines. Thebubble sensor is for alerting the user to the presence of bubbles. Insome embodiments, the bubble sensor may provide a bubble signalrepresentative of an amount of bubbles (volume or number, etc.) in thefuel line. When the bubble signal exceeds a threshold, the user isalerted and may land, e.g. before the turbines fail. The alert may beaudible or visual (for example using the head-up display describedbelow).

A control system 330 is provided. This may be embodied in a singledevice to be worn on the user's chest, or may be formed with distributeddevices. The control system 330 is arranged to provide control signalsto each propulsion assembly 100, 200. The control system 330 may also bearranged to receive control signals from each propulsion assembly 100,200 and/or from the energy storage device 310.

Whilst the control system 330 may independently control the left-handand right-hand propulsion assemblies 100, they may each provide the samethrust.

Thus, in various embodiments the control signals may include: a firstthrottle signal generated by controls 126 of one of the left-hand andright-hand propulsion assemblies 100, and a second throttle signalgenerated by controls 126 of the other of the left-hand and right-handpropulsion assemblies 100. The control system 330 uses the firstthrottle signal to command the left-hand and right-hand propulsionassemblies 100 to each provide a corresponding first thrust. The controlsystem 330 uses the second throttle signal to command the bodypropulsion assembly 200 to provide a second corresponding thrust.

As discussed above, the controls 126 may be embodied as one or two inputdevices the left-hand and right-hand propulsion assemblies 100. In eachcase, one of the input devices provides a variable signal in the form ofthe throttle signal. The other of the input devices (if provided) may bea “kill switch”, which provides a binary output and is monitored by thecontrol system 330 so as to deactivate one or more or all of thepropulsion assemblies 100 of the flight system when released.

The flight system may include a helmet 320 which includes a head-updisplay in communication with the control system 330. The head-updisplay represents the amount of energy remaining in the energy storagedevice 310 (e.g., a volume of fuel remaining in the bladder) and/or thethrust of each of the propulsion assemblies 100, 200 (for example, therotational speeds of the turbines).

Whereas, the flight system 300 of the first embodiment has been shownwith a left-hand propulsion assembly 100, a right-hand propulsionassembly 100, and a body propulsion assembly 200, embodiments areenvisaged in which the body propulsion assembly 200 is replaced by (asin the flight system 500 of FIGS. 5 a to 5 d ), or supplemented with, aleg propulsion assembly 400 (either one for both legs, or one for eachleg).

A leg propulsion assembly 400 includes: at least one leg propulsiondevice 410; and a support 420. The support 420 may be sized and shapedto be worn on a user's calf such that the at least one leg propulsionassembly 410 is on the dorsal side of the calf. The support 420 mayinclude bindings for surrounding the user's leg such that the bindingsdefine a longitudinal axis aligned with the bones of the lower leg.

Some embodiments may have a single leg propulsion device 410. Thesupport 420 may be sized and shaped to be worn on a user's calf suchthat the leg propulsion device 410 is at an angle V to the longitudinalaxis of the support 420 (i.e. is not aligned with the bones of the lowerleg). Angle V is such that when worn, there is a small force appliedinwardly to press the user's legs towards one another. This providesdivergence of thrust when a pair of leg propulsion assemblies 400 areworn and has been found to improve stability. The support 420 may bearranged such that the leg propulsion device 410 is at an angle to thelongitudinal axis of the support 420 of at least 3°. In someembodiments, the support 420 may be arranged such that the legpropulsion device 410 is at an angle to the longitudinal axis of thesupport 420 of no more than 20°. In this way, the leg propulsion devices410 at that angle to the user's leg when worn.

In the embodiments discussed above the left-hand and right-handpropulsion assemblies 100 each included two propulsion devices 110. Insome embodiments, more may be provided, and in fact only one isrequired. Thus, there is envisaged an embodiment of a flight system 600such as that shown in FIGS. 6 a to 6 d , in which each of the left-handand right-hand propulsion assemblies 100 each included a singlepropulsion device 110.

As can be seen from the Figures, in each embodiment of a flight system300, 500, 600, the left-hand and right-hand propulsion assemblies areeach connected to the body propulsion assembly via an articulated frame340, 540, 640. This is merely optional, and in practice, a suitablytrained individual can use the systems without such a frame.

However, a frame 340, 540, 640 is useful for less trained individuals torestrict the relative movement of the left-hand and right-handpropulsion assemblies 100. By providing a set of joints to articulatethe frame 340, 540, 640, predetermined degrees of freedom may beprovided. This can ensure that the left-hand and right-hand propulsionassemblies 100 will always be oriented in an appropriate direction (forexample, the frame 340, 540, 640 can prevent an arm behind positionedbehind the user's back).

The frame 340, 540, 640 would include composite materials and/ortitanium. It may have a hinge under each armpit for allowing adductionor abduction of the arms, a rotational joint between the shoulder andelbow for allowing circumduction of the upper arm, a hinge on the elbowfor allowing the arm to bend, another rotational joint between the elbowand wrist for allowing circumduction of the hand. Merely restricting themotion of the user in this way will help to support the load.

However, it may be advantageous to use a control system having one ormore gyros and/or accelerometers for controlling the frame 340, 540, 640and the thrust applied by the propulsion assemblies 100, 200, 400. Inwhich case, actuators 345, 545, 645 may be provided for actuating thearticulated frame. The actuators 345, 545, 645, may be servos as drawn,or linear actuators (such as pneumatic or hydraulic actuators).

The actuators 345, 545, 645 may be controlled by the control system 330to provide a force towards a position of stability (where horizontalcomponents of the thrust are balanced) based upon signals from one ormore gyros and/or accelerometers forming part of the system. As anexample, this may be carried out using a PID controller to control theangles of the net thrust vectors produced by each propulsion assembly100, 200, 400 so as to provide a predetermined net horizontal thrust(for example zero or a small positive thrust).

Each propulsion device 110, 210, 410 produces thrust in a predetermineddirection. As is known in the art, this may be achieved by acceleratingair and/or combustion products in a longitudinal direction of thepropulsion device 110, 210, 410.

For example, each propulsion device 110, 210, 410 may be a gas turbine.For example, a suitable turbine would be a JetCat turbine available fromJetCat Germany, which is typically used in model aircraft or militarydrones.

Alternatively, a ducted fan driven by an electric motor may be used as apropulsion device 110, 210, 410. If it is required that the system mayfly for an extended period, it is possible that the power supply couldbe connected via a long cable and so need not be carried, therebyreducing the load for the fans.

Whilst the divergent propulsion devices of each propulsion assembly maybe individual turbines (or ducted fans), it is envisaged that thedivergent thrusts may be achieved using a single turbine having two ormore exhaust nozzles that themselves diverge by the stabilizing angles.

Furthermore, whilst wings are not needed for the flight system to fly,these may additionally be provided. For example, a suit forming part ofthe flight system may include a membrane extending between the arms andthe side of the body, or a membrane extending between the legs.Alternatively (or additionally) a rigid wing shaped to provide lift maybe worn on the user's back.

1. A wearable flight system comprising a plurality of propulsionassemblies including a left-hand propulsion assembly configured to beworn on a user's left hand and/or forearm and a right-hand propulsionassembly configured to be worn on a user's right hand and/or forearm. 2.The system of claim 1, wherein each of the left-hand and right-handpropulsion assemblies are arranged to be worn such that in use netthrust is directed substantially in line with the user's respectiveforearm and away from the elbow.
 3. The system of claim 1, furthercomprising a body propulsion assembly comprising a support forsupporting a user's waist or torso.
 4. The system of claim 3, whereinthe left-hand and right-hand propulsion assemblies are each connected tothe body propulsion assembly via an articulated frame whereby theleft-hand and right-hand propulsion assemblies are movable relative tothe body propulsion assembly with predetermined degrees of freedom. 5.The system of claim 4, wherein the articulated frame comprises a set ofjoints to articulate the frame through predetermined degrees of freedom,the joints comprising a hinge arranged to be positioned under an armpitof the user for allowing adduction or abduction of the arm.
 6. Thesystem of claim 4, wherein the articulated frame comprises a set ofjoints to articulate the frame through predetermined degrees of freedom,the joints comprising a rotational joint between the shoulder and elbowfor allowing circumduction of the upper arm.
 7. The system of claim 4,wherein the articulated frame comprises a set of joints to articulatethe frame through predetermined degrees of freedom, the jointscomprising a hinge on the elbow for allowing the arm to bend.
 8. Thesystem of claim 4, wherein the articulated frame comprises a set ofjoints to articulate the frame through predetermined degrees of freedom,the joints comprising a rotational joint between the elbow and wrist forallowing circumduction of the hand.
 9. The system of claim 4, furthercomprising actuators for actuating the articulated frame.
 10. The systemof claim 1 wherein the left-hand and right-hand assemblies each compriseat least first and second hand propulsion units, wherein the two handpropulsion units are arranged either side of a sleeve.
 11. The system ofclaim 10, wherein the handle to be held by a user is mounted in thesleeve.
 12. The system of claim 11, wherein a longitudinal axis of eachof the two hand propulsion units and the sleeve lie in a plane.
 13. Thesystem of claim 12, wherein the sleeve extends over a length of at least20 cm.
 14. The system of claim 1, wherein the left-hand, right-hand, andbody propulsion assembly comprises turbines or ducted electric fans.